Method for pressure cooking canned goods



Oct. 20, 1959 D. H. INGHRAM METHOD FOR PRESSURE COOKING CANNED GOODSOriginal Filed May 26, 1955 INVENTOR. Dupuy/ /NMRAM A TTORNE Y TN mv m zI .m a 5* s.. w mw o United States Patent fO METHOD FOR PRESSURE COOKINGCANNED GOODS Dudley H. Inghram, Omaha, Nebr.

Original application May 26, 1955, Serial No. 511,177,

now Patent No. 2,794,385, dated June 4, 1957. Divided and thisapplication April 15, 1957, Serial No. 652,909

Claims. (Cl. 99-214) The present invention relates to a method forpressure cooking canned goods and is a division of my U.S. Patent No2,794,385, dated June 4, 1957.

The present method is one wherein there is a continuous uninterruptedflow of canned goods and one which assures continuous and uniformcooking temperature and obviates the necessity of repeated handling ofthe goods with a consequent material reduction in the cost of thecooking operation.

Other objects and advantages of the invention will be apparent to thoseskilled in the art and will be understood from the following descriptionwhen read in the light of the accompanying drawings.

In the drawings:

Fig. l is a view partly in section and partly in elevation and to somedegree diagrammatic in nature of an apparatus for practicing theimproved method.

Fig. 2 is a fragmentary enlarged view in vertical section illustratingthe connection between a pair of standpipe sections.

The apparatus used in the practice of my method comprises a pair ofspaced-apart horizontally disposed tanks one of which is a cooking tankA and the other a cooling tank B. These tanks are interconnected by anair lock C the precise purpose of which will be hereinafter described.

At its inlet end 1 the cooking tank is in communication with astand-pipe made up of a plurality of sections 2, 3, 4 and 5 while theoutlet end 6 of the cooling chamber is in communication with astand-pipe made up of a plurality of sections 7, 8, 9 and 10.

The uppermost stand-pipe section 5 has its upper end enlarged to form atank D and the upper section 10 of the other stand-pipe is enlarged toform a tank E.

As will be hereinafter described the cooking chamber A and itsstand-pipe are filled with a liquid and the cooling chamber B and itsstand-pipe are also lilled with a liquid. A steam carrying pipe or pipes11 are disposed in the cooking chamber and are supplied with steam fromsome suitable source of supply, not shown. A refrigerant coil or coils12 are disposed in the cooling chamber and are connected to any suitabletype of refrigerant apparatus, not shown.

An endless type conveyor F is horizontally disposed within and extendslengthwise of the cooking chamber and an endless type horizontallydisposed conveyor -G extends lengthwise of the cooling chamber. Avertically inclined endless type conveyor H extends upwardly from thedelivery end of the conveyor F and terminates in the air lock or airchamber C at a point above the reception end of the conveyor G.

A tank I containing compressed air provided from any suitable source,not shown, has an outlet pipe 13 adapted for communication with theinterior 14 of the air lock. A normally closed valve 15 is in the airline 13 and is operated by a float 16 disposed within the air lockchamber on the surface of the cooking uid K.

-v The cooking duid or solution is water, but it could be any otherliquid of substantially the same specic gravity as water with a boilingpoint in the neighborhood of 300 F.

The cooking fluid or solution completely fills the cook ing tank and thestand-pipe thereof. It will appear later that as cans are conveyed toand deposited in the cooking chamber stand-pipe these will displacewater and to maintain the proper water level, which is indicated at 17at the top of the stand-pipe and at 18- within the air lock, thisdisplaced water islpermitted to overflow the upper edge 19 of theuppermost stand-pipe section 5 and ow into the overflow tank L.

A supply of Water for the cooking side or system of the device ismaintained in the tank M. A ilexible pipe 20 interconnects thisreservoir and the tank L through a pump 21 and a second pipe 22 at thebottom of the overow tank.` The pump 21 will return the overow fluid tothe reservoir. A third pipe 23 delivers water from the reservoir to theupper end of the uppermost stand-pipe section 5. This pipe intermediateits length is provided with a normally closed Valve 24 which is moved toopen and closed positions by a float operator 25.

The cooking end of the apparatus is the receiving end and filled andsealed cans are suitably delivered to a reception tank N having thereina liquid 26 of high speciiic gravity within which the cans will oat.There is an endless type conveyor O having thereon a plurality of pusherblades 27 which pass over and extend slightly down into the iluid 26within the reception tank. This conveyor operates to engage cansfioating in the tank and pushes them up the inclined ramp 28 thereof anddumps them in the water K at the upper end of the cooker chamberstand-pipe section 5.

The cooling chamber and the entire associated and communicatingstand-pipe are filled with a cooling solution having a high specificgravity and one sufficiently high so the filled cans will float therein.This cooling liquid or solution is designated as an entirety by P anditslevel within the air lock is indicated at 29 and within the tank E at60.

The levels of this Huid will vary in accordance with the number of canstraveling through the cooling side of the mechanism and accordinglyprovision for handling overflow fluid and supplying additional fluid isprovided.

There is an overflow tank Q and a supply tank or reservoir R. The bottomof the overflow tank is connected with the reservoir through the pipes31 and 32 in which a pump 33 is disposed, Liquid is replenished to thisside of the system from the tank R to the tank P through the flexiblepipe 34 having in its length a Ynormally closed Valve 35 which isoperable to open and closed positions by the float 36.

An, endless type conveyor similar to the conveyor O described isassociated with the tank In. 'Ihis conveyor S provided with a pluralityof pusher blades 37 to travel over and in the surface ofthe fluid withinthe tank P and engages the floating cans and pushes them up the inclinedramp38 Where they are delivered to any suitable conveyor system whichwill take them to what is known asthe case off room of the packingplant.

' VAn insulated barrier or dam T extends across the air lock chamberbeneath the conveyor H and prevents the cooling fluid from reaching thecooking chamber. The fluids are also prevented from joining by reason ofthe air pressure which is maintained in the air lock. The degree of thisair pressure will be referred to hereinafter.

The degree of pressure and its maintenance within the system and themanner in which it may be varied will now be described. For every twofoot of height of liquid in the stand-pipes there is approximately onepound of pressure. The stand-pipes accordingly are made of the `properlength-to provide the proper pressure within,

the lower chambers. Once the stand-pipes are made of the proper heightsno alteration or change is necessary where a single product is to beprocessed. Where different pressures are desired or necessary it isintended to add or remove intermediate stand-pipe sections. For thisreason a simple yet efficient joint is provided between the abuttingends of sections. In Fig. 2 the upper end of section 3 and the lower endof section 4 are illustrated. Here it will be seen that section 3 isprovided at its upper end with a groove 39 having in its bottom apacking 40. The lower end of the pipe section 4 is provided with acircumferential tongue 41 which extends into the groove and rests uponthe packing. As will hereinafter appear, there is always weight uponthese -sections and it has been found that the joint described isadequate to prevent leakage.

By reason of the adjustability of the heights of the stand-pipes it isnecessary to provide means for raising and lowering the loading andunloading facilities or mechanisms of the system. This could be done inmany ways other than that illustrated and now to be described.

The device illustrated for raising and lowering the loading facilitiesof the device comprises a platform V and a pair of hydraulic lifts eachembodying a lift cylinder 45 and 46. At one end the platform is providedwith an elevated portion 47 upon which the reception tank N rests and atits other end the platform is provided with an end wall 48 upon whichthe top 49 of the overflow tank rests.

No illustration is made of the mechanism for operating the hydrauliclifts as such devices are well known and understood and are commonlyused. One place where lifts of this kind are in common use is in servicestations for raising automobiles for lubricating jobs.

A cylinder lift is provided for the unloading facilities of the device.In this instance the platform is 51 and the hydraulic lift pistons orcylinders are 52 and 53. An end wall 54 of the platform supports one end55 of the overflow tank top While an elevated or raised portion 56 ofthe platform is beneath the opposite end 57 of the tank top.

It will be seen that through proper positioning of the elevating means aportion of the weights of the loading and unloading mechanisms can beplaced upon the upper stand-pipe sections 5 and 10 with the result thatthe section interconnections, illustrated in Fig. 2, are renderedliquid-tight due to the engagement under pressure of the tongue of onesection with the packing in the groove of the other section.

The coolant tluid in the cooling end of the mechanism is one which is ofsutliciently high specific gravity that the loaded and sealed cams willfloat therein. There are numerous such fluids, one of which is aconcentrated solution of calcium chloride.

The purpose of the air lock C, in addition to providing an apparatusthrough which the cans can be continuously progressed without the lossof pressure in the cooking section of the device, yis to maintain thepressures constant in both the cooking and cooling sections of theapparatus and to maintain the liquids at the proper level. The pressurewithin the air lock will be maintained at the same pressure exerted uponthe `lluids in the chambers A and B by the lluids in the twostand-pipes. If the pressure brought about by the pressure in thestandpipes is seven pounds per square inch, that will be the pressuremaintained in the air reservoir I. However, the maintenance of theproper pressure in the air lock could be accomplished by means of apressure control valve in the air line 13 should it be so desired. Sucha regulator would be set for the proper air pressure which should bemaintained in the air lock.

Obviously the air or gas pressure in the air lock will maintain thelluids at their proper levels and prevent them overflowing or lling theair lock. The'pressure in the air lock accordingly constitutes a dam orbarrier which prevents the cooking fluid from reaching and comminglingwith the coolant fluid.

There is no illustration of the drive means for any of the endlessconveyors. It is intended that there be speed regulators for the drivemeans of these conveyors but inasmuch as speed regulators for conveyorsare old and well known, illustration of them is considered unnecessary.There are many speed regulated conveyors on the market and the one mostsuited to the present apparatus would be selected.

Attention is directed to the fact that the cooking fluid could be an oiland the coolant fluid water. With these particular fluids there would bea natural separation of the cooking tluid Afrom the coolant tluid whenthe two become mixed with one another by a carry-over of the cookinglluid into the coolant iluid from the cans. Cooking tluids carried overinto the coolant iluid could be re-claimed by a simple run-off method.

Having described an apparatus by which the present improved method canbe practiced, a short description of the operation of the apparatus willnow be given.

The method is intended for use on large scale operations in which cansmay be lled and sealed at the rate of as high as eight to ten thousandcans per hour. The capacity of the present device is not limited asenlargement of the overall size of the parts making up the apparatuswould result in increasing its capacity, as will be readily apparent.

The present method might well be called a sink and float method in thatthe cans are permitted to sink into the cooker portion of the apparatusand iloat outwardly from the cooler portion of the apparatus. The feedto the device is or can be continuous and reduces to the minimum themanual labor incident to a pressure cooker for canned goods.

The filled and sealed cans are suitably brought to and dumped into `theliquid within the reception tank N in which they will float. The cansare pushed from this tank by the conveyor O into the enlarged upper endD of the stand-pipe section 5. Water within this stand-pipe and also thecooking chamber at the lower end thereof is maintained, by the heatingpipes or elements 11, at the proper temperature to properly cook thecontents of the cans.

Immediately upon entering the upper end D of the stand-pipe section 5the cans sink to the bottom onto the conveyor F in the cooking chamber.Here the water is at the proper temperature and is maintained at thedesired pressure by making the stand-pipe of the proper predeterminedheight. The pressure within this charnber can be varied by inserting orremoving stand-pipe sections.

At this point it might be pointed out that the stand-pipe for thecooking chamber could be disposed at an inclination to the vertical ifit were found that the cans sink so rapidly downwardly through thestand-pipe as to injure them when they reach the bottom and contact theconveyor.

Upon reaching the conveyor F the cans are conveyed through the cookingsolution within the cooking chamber A. Through proper setting of thespeed regulator the cans will be caused to remain in the cookingsolution the proper length of time to be properly cooked.

As the cans enter the stand-pipe and leave the cooking chamber the levelof the liquid will be caused to rise and fall which would vary thepressure at the bottom of the stand-pipe, that is, within the cookingchamber. To prevent this variation in pressure the hereinbeforedescribed manner of permitting an overflow of Water from the topstand-pipe section S is provided. Should more cans be leaving thecooking chamber than are entering, the level of the liquid would falland this would result in the actuation of the float valve 25 to causethe liquid level to be immediately brought back to the proper level.

When the cans reach the end of the conveyor F they fall upon theconveyor H and are carried through the air lock C and are dropped offinto the coolant fluid 29 within the cooling portion of the apparatus.As pointed out, this coolant liuid has a specic gravity such that thecans will yfloat therein. The cans accordingly remain above the conveyorB and are carried or pushed by that conveyor to the lower end 6 of thestand-pipe made up of the sections 7 to 10 inclusively. The adjustmenton the speed regulator drive of this conveyor is made such that the canswill remain in the chamber B the proper length of time to be adequatelycooled.

Immediately the cans reach the lower end of the standpipe they floatupwardly into the discharge tank P and loat up against the conveyor S bywhich they are pushed up the ramp 38 for discharge to proper conveyingmeans which will carry them to the case off room of the establishment.

The liquid level can change in the cooling portion of the apparatus byvariance in the delivery of cans into this section of the device and inthe delivery of the cans from the discharge tank. VIt will be understoodtha-t the liquid of the coolant is maintained through provision foroverflow into the overflow tank Q and the delivery of additional fluidunder the control of the iloat valve 36.

Most canned products have almost neutral buoyancy in water. Where thebuoyancy of the filled cans is such that they will float in water aslightly different arrangement is necessary, as will be hereinafterdescribed.

Inasmuch as it takes a greater length of time to perform the cookingoperation than the cooling operation there should be no crowding orjamming up of cans in the cooling side of the apparatus. In any eventproper adjustments of the several conveyors will assure proper andcontinuous lllow of cans through the apparatus.

The apparatus has the particular desirable attribute that it will handlecans of any size or shape without alteration of the mechanism. Actuallycans of different sizes and shapes can be processed at the same timeprovided the cooking periods for the contents of the cans is the same orsubstantially the same. This is a particularly desirable attribute aswhere changes or alterations are necessary for handling cans of diierentsizes and shapes a great deal of time is lost which increases materiallythe cooking operation.

Departures from the specific mechanical arrangements shown and describedcan be made without departing from the inventive concept. Where thenature of the canned goods is such that the cans depart from neutralbuoyancy in water, such as for instance shoe-string potatoes, cans ofthis material would have to be conveyed through the apparatus in coveredbaskets. To provide for this would not be dillicult. The conveyors F, Gand H would be eliminated and a continuous conveyor extending from theupper stand-pipe section 5 4through the cooking chamber, air lock,cooling chamber and upwardly out of the standpipe for the coolingchamber would be provided. The baskets would be suitably secured to thisconveyor and carried through the machine by lthe conveyor element.

The fluid in the can reception tank N and in the coolant side of theapparatus is identical and hence fore not be delivered to the cookerchamber.

The apparatus illustrated and described is to be co11- sideredillustrative of the inventive concept and not limitative thereof. Ifspace is an important consideration space could be saved by incliningthe two stand pipes toward one another. Additionally by the use ofproper conveyors and proper shaping of the air lock the coolant chambercould be positioned to parallel the cooking chamber.

What I claim is:

l. The method of continuously processing canned goods comprising,progressing the cans through a heated liquid having a speciiic gravitysuch that the cans will sink therethrough, then progressing the cansthrough a chilled liquid having a specific .gravity such that the cansfloat therein, and then removing the cans from the surface of thechilled liquid.

2. A method as defined in claim l wherein, the chilled liquid is acalcium chloride solution.

3. The method of continuously processing canned goods which comprises,delivering the filled and closed cans into a conned vertical column ofliquid having a specific gravity such that the cans will sinktherethrough, progressing the cans throulgh a horizontally extendingconfined body of liquid which communicates with the lower end `of saidvertical liquid column and which is heated to a temperature such thatthe contents of the cans will be properly cooked, progressing the cansthrough said horizontally extending body of liquid and into a secondhorizontally extending enclosed body of liquid which is out of contactwith the iirst named body of liquid and which has a specific gravitysuch that the cans will float therein, progressing the cans through saidsecond body of liquid and into and through a communicating confinedvertical column of like liquid, chilling the liquid constituting thesaid second body of liquid and the liquid comprising the last namedvertical column, permitting the cans to lloat to the top surface of thelast named Vertical column of liquid, and then removing the cans fromthe top of said vertical liquid column.

4. A method as defined in claim 3 wherein, the chilled liquid is acalcium chloride solution.

5. A method as delined in claim 3 wherein, an air lock which is incommunication with both horizontally extending bodies of liquid isprovided to prevent contact between said bodies of liquid, maintaining apressure in said air lock equal to the pressure exerted upon the liquidsin the horizontally extending bodies of liquid by the vertical columnsof liquid, and mechanically progressing cans through said air lock fromthe heated liquid to the chilled liquid.

References Cited in the file of this patent UNITED STATES PATENTS1,377,088 Martin May 3, 1921 1,584,397 Paxton May 11, 1926 2,710,260Reed .Tune 7, 1955

1. THE METHOD OF CONTINUOUSLY PROCESSING CANNED GOODS COMPRISING,PROGRESSING THE CANS THROUGH A HEATED LIQUID HAVING A SPECIFIC GRAVITYSUCH THAT THE CANS WILL SINK THERETHROUGH, THEN PROGRESSING THE CANSTHROUGH A CHILLED LIQUID HAVING A SPECIFIC GRAVITY SUCH THAT THE CANSFLOAT THEREIN, AND THEN REMOVING THE CANS FROM THE SURFACE OF THECHILLED LIQUID.